The present invention relates to an apparatus, system and method of providing wireless communication devices in discs and communicating of information concerning the disc containing the wireless communication device.
It is often desired to track and identify items, such as packages, containers, discs, etc., and to communicate information concerning such items wirelessly. One method of tracking and providing information concerning packages is to attach a wireless communication device, such as a radio frequency identification (RFID) transponder or other identification device, to packages. The information communicated concerning the packages may include identification information, expiration dates, xe2x80x9cborn onxe2x80x9d dates, lot numbers, manufacturing information, and the like. A wireless communication device may be attached to an individual package or to a container containing multiple packages.
A problem exists when a wireless communication device is attached to packaging or containers constructed out of a conductive material such as foil, or comprised of a metalized or conductive portion. A pole antenna connected to the wireless communication device will not radiate properly if the wireless communication device is attached on the outside of the package. The pole antenna will be shielded if the wireless communication device is placed inside the package.
In addition to conductive materials, wireless communication devices are also used with many other substrates. Each substrate has its own dielectric characteristics that typically affect the impedance matching between the wireless communication device and its antenna. Impedance matching ensures the most efficient energy transfer between an antenna and the wireless communication device.
One particular item for which tracking may be desirable is a disc. Discs can be any type of circular substrate, but the present invention address discs that store digital information in particular such as compact discs or mini discs. Note that in this context, the term xe2x80x9cmini discxe2x80x9d does not refer to the trademark used by SONY, but rather to a miniature compact disc that is optically read. Most compact discs and mini discs are made from a metalized outer portion and a plastic inner portion. Digital video discs or Digital versatile discs (collectively DVDs) are made from substantially the same structure. This tracking may be for identification, such as in a retail outlet, computer system or jukebox (for compact-discs), theft prevention, authenticity purposes or the like as needed or desired.
It may be also advantageous for such a wireless communication device to communicate on different frequencies so that one device can be used for various applications. For instance, an operating frequency of 2.45 GHz is used frequently outside the United States, but an operating frequency of 915 MHz is frequently used in the United States. Many companies manufacture wireless communication devices that are capable of operating at both 915 MHz and 2.45 GHz frequencies so that either frequency can be chosen for operation. However, wireless communications device applications, such as attaching wireless communication devices to packages for informative and tracking purposes, configure the device to communicate on only one frequencyxe2x80x94either a frequency for the United States or a frequency for use abroad. It would be advantageous to construct a wireless communication device with an antenna structure that is capable of communicating at more than one frequency. This would allow one wireless communication device to be applicable for uses in both the United States and abroad.
The present invention relates to a wireless communication device for use in conjunction with a disc, such as a compact disc, mini disc or digital video disc, or comparable item. In particular, an antenna is formed with a conductive tape or the like attached to a center portion of the disc. The metalization of the disc coupled with the tape, form a slot antenna for operation at a first frequency. Further, conductive tabs may be used to couple to the slot in such a fashion that the tabs form an antenna at a second frequency. These conductive tabs may also serve the purpose of delimiting the length of the slot regardless of their use as a second antenna.
It should be appreciated that the parent applications discussed wireless communication devices associated with a package, container or other material to communicate information concerning the package, container or other material. A wireless communication device is provided that contains a control system, communication electronics, memory, and an antenna. The wireless communication device may contain a sensor to sense environmental conditions surrounding the wireless communication device. The wireless communication device contains one or more tabs constructed out of conductive material. The tab(s) may serve as both a pole antenna and may attach the wireless communication device to a slot, thereby forming a slot antenna. While helpful in some embodiments such is not required in all the embodiments herein presented.
In one embodiment, the wireless communication device is a transponder that is interrogated by an interrogation reader for communication purposes. The wireless communication device is attached to a package that may be constructed out of a conductive material, such as foil packaging used for food or liquid.
In another embodiment, the tab(s) form a pole antenna to communicate in a first mode at one frequency, and the tab(s) are attached across a slot in a package to communicate in a second mode at a second frequency. One tab is used in one embodiment to form a monopole type antenna, and two tabs are used in another embodiment to form a dipole antenna. In another embodiment, the tab(s) can be varied in shape and size to adjust to surfaces that vary in form.
An asymmetrical antenna arrangement may be provided so that the impedance of the antenna is not substantially affected by the substrate to which the wireless communication device is attached. In one embodiment, the asymmetrical antenna arrangement is an asymmetrical dipole antenna formed by asymmetrical tabs. For example, the wireless communication device may be placed in an indentation in the substrate so that the wireless communication device does not protrude from the substrate surface. Asymmetrical tabs are placed on the surface of the substrate. The asymmetrical tabs are connected to the wireless communication device with feed lines to provide an asymmetrical dipole antenna. In a second embodiment, the asymmetrical antenna arrangement is an asymmetrical slot antenna.
In another embodiment, a wireless communication device placed onto a disc, such as a compact disc or video disc, is used in conjunction with an interrogator to identify a disc for either promotional or security purposes. A customer may purchase a compact disc or video disc in a retail store. As the customer leaves the retail store, an interrogator determines the identification of the disc purchased by the customer and displays and/or plays a special message to the customer. If an interrogator detects an unpurchased disc leaving the retail store, the interrogator may indicate an alert and/or alarm condition.